Sex Hormone Lessens Snacking

Add another credential to oxytocin's impressive resume: the hormone crucial for bonding also reduces the calories people consume when they are snacking for pleasure, making it a possible therapeutic target for obesity.

German researchers gave a group of men a dose of oxytocin thought to be roughly the amount released by the brain after breast-feeding or sex, according to lead author Manfred Hallschmid of the University of Tübingen. These men and another group who took a placebo then had a chance to eat as much as they wanted at a breakfast buffet, and later the same day they were offered snacks. Those who took oxytocin ate fewer snack calories, but the hormone did not change how much the men ate during the main meal, suggesting that oxytocin affected pleasure eating without suppressing normal appetite mechanisms.

The researchers hypothesize that the hormone diminished reward-seeking behavior initiated in the ventral tegmental area of the brain, a region found to be highly sensitive to oxytocin in rodent studies. The effect may also be stress-related: subjects who took oxytocin saw a drop in their levels of the stress hormone cortisol, according to the paper published in 2013 in the journal Diabetes. More work is needed to understand whether oxytocin could be used to treat obesity, but until then the finding at least hints that it may be possible to curb your cravings by having more sex.